The OCBD is not meant to be slim slim fit but BBs are like a tent with good material and collar roll.
The obsessives now look to Mercers Shirts online - but even then the cognoscenti go for right size in collar and down one size or so in the rest of the shirt - complicated - and these are people who like a slightly "generous" fit. Mercers are reputed to be good but neither cheap nor fast.
I've got some old used "vintage" BB and LL BEAN oxfords and they are great for material and collar roll but would sleep a family of 4.
There is a consensus amongst those who study these things that the LE Hyde Park "Tailored fit"must iron is the best all round for collar roll and price and fit. There is a nasty rumor around that in the last couple of months the collar peak has shortened by .5" - yet to be confirmed. If true it will be a scandal and big blow.